Genetic stability of net x spot hybrid progeny of the barley pathogen Pyrenophora teres
Hybrid progeny produced from a mating between a net- and a spot-type isolate of the barley net blotch pathogen Pyrenophora teres were screened to assess their viability and genetic stability. Progeny (F1) inoculated onto seedlings of the barley cultivars Stirling (highly susceptible to net-, and slightly susceptible to spot-type isolates), B87/14 and Clipper (only susceptible to spot-type isolates) produced jagged-type symptoms on all cultivars. When cultures (F1-1) isolated from leaves inoculated with F1 cultures were inoculated onto these cultivars, they produced similar symptoms. F1-2 cultures isolated from F1-1 infections also produced similar symptoms. RAPDs produced on all isolates of F1-1 and F1-2 progeny revealed identical profiles to those obtained for F1 isolates. Molecular and infection data indicated that jagged-type hybrid progeny of this net x spot mating retained their virulence and fertility over time, and were genetically stable after two cycles of inoculation, mitosis and re-isolation. Hybridisation between net- and spot-type isolates of P. teres may, therefore, play a significant role in net blotch epidemiology in barley-growing areas.